Method for combatting rodents and rodenticidal compositions

ABSTRACT

This invention relates to a method for combatting rodents (especially animals which belong to Muridae) comprising applying a rodenticidally effective amount of a compound of general formula (1)   WHEREIN R1 is hydrogen or an alkyl group, R2 is an alkyl group, R3 is hydrogen or an alkyl group and R4 is hydrogen, hydroxyl group, an alkyl group, a hydroxy-substituted alkyl group, benzoyl group or a halogen substituted phenyl group, or an acid addition salt thereof, and to rodenticidal compositions containing said compound or salt together with adjuvants.

United States Patent 1191 Yamamoto et al.

[451 July 1, 1975 METHOD FOR COMBATTING RODENTS AND RODENTICIDAL COMPOSITIONS [75] Inventors: Hiroshi Yamamoto, Tokyo; Shoichi Kato, Ageo; Koji Ohgushi; Iwao Tokumitsu, both of Fukuoka, all of Japan [73] Assignee: Nippon Kayaku Co., Ltd., Japan [22] Filed: Sept. 5, 1972 [21] Appl. No.1 286,058

[30] Foreign Application Priority Data OTHER PUBLICATIONS Chem. Abst. 39, 2811(8), (1945), Dieke and Richter Toxicity of Thiourea to rats. Chem. Abst. 41 6662(g), (1947).

Primary ExaminerAlbert T. Meyers Assistant ExaminerDouglas W. Robinson Attorney, Agent, or FirmRussell & Nields [57] ABSTRACT This invention relates to a method for combatting rodents (especially animals which belong to Muridae) comprising applying a rodenticidally effective amount of a compound of general formula (1) Nl-lC /3 (1) wherein R is hydrogen or an alkyl group, R is an alkyl group, R is hydrogen or an alkyl group and R, is hydrogen, hydroxyl group, an alkyl group, a hydroxysubstituted alkyl group, benzoyl group or a halogen substituted phenyl group, or an acid addition salt thereof, and to rodenticidal compositions containing said compound or salt together with adjuvants.

5 Claims, No Drawings METHOD FOR COMBATTING RODENTS AND RODENTICIDAL COMPOSITIONS DETAILED EXPLANATION OF THE INVENTION Heretofore, various rodenticides, in particular raticides have been developed. They are, however, linked with toxicity to men and cattle and their repelling property and any one of them are not satisfactory yet. For example, N-( l-naphthyl)thiourea, which is now widely used under the trade name ANTU have the disadvantage that, although of relatively low toxicity to human being, it will repel, once it is used, the rats in the applied area and prevent their access for bait over a considerable length of time.

We have made extensive research for those rodenticidal compounds eliminating these drawbacks and now found that compounds of the above-described general formula (1) have strong toxicity to rodents and relatively weak repelling property to maintain good rodents access for bait, while having low toxicity to useful animals such as dogs, on which finding the present invention has been achieved.

Compounds used in the present invention may be prepared for example, by adding the corresponding aniline to a solution of benzoyl chloride and ammonium rhodanide in acetone, and boiling the mixture to condense the reactants. They may also be prepared by condensing phenyl isothiocyanate with the corresponding amine in the presence or absence of an appropriate solvent. Alternatively, compounds of general formula 1) wherein R and R, are both hydrogen may be prepared by hydrolyzing a corresponding phenyl-3- benzoylthiourea with an aqueous sodium hydroxide solution. Acid addition salts include salts with hydrochloric acid, sulfuric acid and the like,

Compounds of general formula (1) used in the present invention may be applied by itself for combatting rodents by applying them to passages of rodents, but

normally they are used together with adjuvants and a composition of the compound with adjuvants (for example carrier etc.) may be applied for combatting rodents by any suitable means, as by applying the composition to passages of rodents or by placing the composition as bait or poisonous drinking water where rodents are accessible to the bait or water.

As carrier, one may employ, for example, solid materials such as starch, kaolin clay, montmorillonite clay, diatomaceous earth and sugar, liquid materials such as xylenes, chlorobenzenes and the like aromatic hydrocarbons, methanol, ethanol and the like alcohols, ethanolamine and the like amines, aliphatic esters and water and favourite diets of rodents such as meats, meat extracts, rice, wheat flour, buckwheat flour, corn flour and the like cereals, sugar-cane, potato, seeds of sun flower, fish meal, fruits, vegetables and the like.

Compositions of the present invention may be used as rodenticidal compositions in form of powder, granules, pellets, solution, suspension, emulsion, paste and the like convenient form, optionally with the aid of an adjuvant such as carrier an emulsifying agent or a dis persing agent.

As emulsifying agents, one may employ, for example, nonionic and anionic emulsifying agents such as fatty acid ester or phosphoric acid ester of polyethylene glycol. As dispersing agents, one may employ, for example, calcium sulfonate.

The rodenticidal composition of the invention normally contains a compound of general formula (1) in concentrations of from 0.05 to preferably from 0.5 to 90% by weight.

Rodents which can be combatted according to the present invention include rats (Genus Rattus) and squirrels.

Representative examples of active compounds used in the present invention are given in Table 1.

Table I Compound Compound Appearance m.p.

l 4-methylaminophenylthiourea white needle- 176 177C like crystals 2 4-dimethylaminophenylthiourea white needle- 194 196C like crystals 3 4-diethylaminophenylwhite needle- 168 169C thiourea like crystals 4 4-di-n-propylaminophenyllight yellow I30 131C thiourea plate like crystals 5 4 di-n-butylaminophenylwhite needle- I07 108C thiourea like crystals 6 4-di-n-amylphenylthiourea white plate- 121C like crystals 7 4-dimcthylaminophcnyl- Gray crystals 191 195C thiourea dih drochloridc (with decom sition) 8 N-hydroxy- -4-dimethylamino- White crystals 91 92 C phcnylthiourea 9 N-ethyl-N'-4-dimethylamino' 142 143C phcnylthiourea 1O N,N-diethyl-N'4dimethy1 1 l2 l 13C minophenylthiourca l l N-dodecyLN'-4-dimethylamino- 73 74C phenylthiourca l2 N-2-hydroxyethyl-N'-4- 174 175C dimcthylaminophcnylthiourca l3 N-4-chlorophenyl-N-4- 196 197C dimcthylaminophcnylthiourea l4 Nbenzoyl-N"4-diethylamino- Light ycllow 132C phcnylthiourca needle-like crystals The following experiments illustrate that the active ingredient according to the present invention has excellent rodenticidal effects.

Experiment 1. Acute oral toxicity A 3% starch solution was prepared, boiled and cooled and a given amount of a compound of general formula (1) was suspended therein. Test Norway rats were each orally given 2 ml of the suspension and then fed. After days, inspection was made whether the animals survived or died. The results are shown in Table 2.

tom surface of the tunnel was placed a vat of cm in width and cm in length scattered with a tale-based powder preparation containing the particular compound (Compound No. 2) in a concentration of 10% as prepared by the method described in Example 1 Test animals 1 male, 3 females, 4 animals in all, total body weight 790 g, mean body weight 198 g) were released in the cage. .It is understood that the animals will walk on the powder-sprayed surface at every egress and ingress. Inspection was made for daily diet intake, the amount of the powder preparation consumed and the number of death. The results are shown in Table 4.

Experiment 3. Toxicity test by powder-scattered surface walking technique Table 2 Compound Test animals Dose orally Raticidal efiect No. Body weight sex administered in mg/Kg Survival or Length of time death until death I l 10 male 300 Died within 1 day 150 female 200 Survived 2 female 200 Died within 1 day 150 male 3 l30 male 200 100 female 100 4 I20 male 300 5 95 male 200 male 100 Survived 6 I00 female 200 Died within 1 day 130 male 100 Survived 7 male 100 Died within 1 day Experiment 2. Toxicity test by free feeding technique 30 Table 4 After 1 day After 2 days A single Norway rat was housed in each test cage (25 Dlfit Intake I g 0 er amma cm width X 35 cm length X 20 cm height) and was fed amount of overnight by placing in the cage 10 g of a bait contamthe powd r 0 73 0 ing the active ingredient as prepared by the method de- 35 $223238? g scribed in Example 3 in a concentration of 1.0%, with animal Cumulative said bait contained in a tall skirted Petri dish. Inspec number of 3 animals 4 animals tron was made for the amount of the bait eaten (bait mdeath (1 male, 2 f l take) and for the fatal effect of the active ingredient gia 75 100% during 3 days. The results are shown in Table 3. 40 a Table 3 Com ound Test animals Bait Effect 0. Species Body weight Bait in Active ingredients Survival Length of time sex in g take in g intake mg/Kg or death until death l Norway 285 male 1.8 63.2 died within 1 day rat 230 male 0.5 21.7 died 335 male 1.4 41.8 died 245 male 19 77.6 died 2 male 0.5 25.6 died 50 male 0.5 320 died Roof I25 male 2.2 176 died within 2 days rat 3 Norway 130 male 3.] 238 died within 1 day rat 220 male 0.5 22.7 died within 2 days 7 140 female 0.5 36.7 died within l day Experiment 4. Repelling property of baits A single brown rat was housed in each wire netting test cage of 25 cm in width, 25 cm in length and 35 cm in height, fed overnight with 10 g non-poisonous feed as prepared by the similar method described in Example 3 contained in a tall-skirted Petri dish and further fed overnight with 10 g bait containing the active ingredient [Compound No. 2 or ANTSU (Trade name)] contained in a tall-skirted Petri dish. Feed or bait intake was examined in the respective cases. 20 Norway rats were used for each of the active compound containing baits.

The repelling property of the respective baits were evaluated by the relative repellency which is defined by 5 the following equation:

Table 7 Com- Test animals Bait Effect pound No. Body weight Sex Intake Active ingredient Survival Length of time in g in g intake mg/Kg or death until death 8 170 Male 1.6 940 Died within 4 days 200 2.3 1 l5 within 2 days 9 240 0.1 16.5 within 3 days 205 0.1 4.9 within 4 days 10 115 4.8 417 within 2 days 185 Female 0.3 16.2 within 4 days 1 1 255 Male 3.8 419 within 2 days 220 Female 2.5 1 l7 Survived 12 225 Male 2.3 102 Died within 2 days 185 Female 1.3 70.2 within 4 days 13 215 Male 1.8 83.7 within 3 days 190 4.4 232 Survived 14 240 2.1 87.5 Died within 2 days 165 Female 0.8 48.5 within 2 days Non-poisonous feed intake bait intake Relative repellency bait intake The results are shown in Table 5 in which the numerical values for relative repellency are averaged ones.

Experiment 5. Toxicity to dogs Cream bun was cut into pieces as large as hens eggs and the pieces were provided in the central portion The present invention will be further explained with some of the compounds according to the present invention. It is understood, however, that the contents of the active ingredients and additives may vary over a wide range. In these examples, all percentages are by weight.

EXAMPLE 1 Compound No. l 10 talc 90 are admixed to give a powder preparation.

EXAMPLE 2 Compound No. 6 Starch are admixed and 10 parts of the admixture is sprinkled on 100 parts of sweat-cane, potato, bread or fried beancurd to give a bait.

thereof with a hollow. To this hollow was added milk EXAMPLE 3 together with Compound No. 2 to embed the latter in the hollow. The cream bun pieces thus treated were Compound 2 1% given to dogs by hand. The results are shown in Table corn flour 10 6.

Table 6 Dose Survival administered Test dogs or in mg/kg Species Color of fur Body;; weight Age in years Death 100 Mongrel light brown 10 kg 2 Survived Female 400 Black 7 kg 1 Survived 600 Brown 12 kg male 4 Survived Experiment 6 buckwheat flour 1o wheat flour 65 A single Norway rat was housed in each of test cages bran i0 fish meal 4 of 25 em in width, 35 cm in length and 20 cm in height are admixed and 100 parts of the admixture is kneaded with 20 parts of water added and formed into cylindrical granules, which are then dried to give a bait.

EXAMPLE 4 Compound No. 8 l Starch 45 molasses 25 meat extracts 5 sesame oil are admixed and 10 parts of the admixture sprinkled on 100 parts of sweat-cane, potato, bread, fried beancurd or the like to give a bait.

EXAMPLE 5 Compound No. 11 l soluble starch 20.9 sugar 5 sodium benzoate 0.1 water 73 are admixed to give an aqueous bait.

EXAMPLE 6 Compound No. 14 1 wheat flour 69 sugar 5 sesame oil 5 water are kneaded and formed into doughboys each weighing 0.5 g to give a bait.

EXAMPLE 7 Powdered Compound No. 8 is applied as such to a passage of rats.

EXAMPLE 8 Powder of Compound No. 8 is applied to sweet potato cut into cubes 3 mm cube in a manner such that the content of said compound may become 1%, to give a bait.

EXAMPLE 9 Grains of wheat are dipped in a 10% aqueous sugar solution and powder of Compound No. 2 sprinkled on the solution to give a bait.

EXAMPLE 1O 20 parts of water is added to 100 parts of corn flour and kneaded therewith and 10 parts of powder of Compound No. 3 is admixed with the dough to give a bait.

EXAMPLE 1 1 1 part of powder of Compound No. 6 is suspended in 8 parts of an edible oil to give a bait or a sprinkling composition.

EXAMPLE 12 Powder of Compound No. 8 is sprinkled on bread impregnated with a 10% aqueous sugar solutions give a diet.

What is claimed is:

1. A method for combatting rodents comprising the step of making accessible to rodents a feed bait containing a rodenticidally effective amount of a compound of the formula wherein R is hydrogen or alkyl of l to 5 carbons, R is alkyl of l to 5 carbons, R is hydrogen or alkyl of 1 to 2 carbons, and R is hydrogen or alkyl of 1 to 12 carbons, or a hydrochloric acid salt thereof.

2. The method as claimed in claim 1, wherein said compound is wherein R, is hydrogen or alkyl of 1 to 5 carbons and R is alkyl of 1 to 5 carbons.

5. The composition for combatting rodents as claimed in claim 4, wherein said rodents are animals which belong to Muridae. 

1. A METHOD FOR COMBATTING RODENTS COMPRISING THE STEP OF MAKING ACCESSIBLE TO RODENTS A FEED BAIT CONTAINING A RODENTICIDALLY EFFECTIVEE AMOUNT OF A COMPOUND OF THEE FORMULA
 2. The method as claimed in claim 1, wherein said compound is
 3. The method as claimed in claim 1, wherein said rodents are rats (Genus Rattus).
 4. A rodenticidal composition comprising a feed bait containing a rodenticidally effective amount of 99.5 - 10% by weight of a suitable adjuvant and 0.5 - 90% by weight of a compound of the formula
 5. The composition for combatting rodents as claimed in claim 4, wherein said rodents are animals which belong to Muridae. 